Clinical characteristics and outcomes of women with adenomyosis pain during pregnancy: a retrospective study.

OBJECTIVES: Adenomyosis is associated with unfavorable perinatal outcomes, and recent case reports show that some women with adenomyosis experience pain at the adenomyosis lesion during pregnancy and have detrimental perinatal outcomes. This study aimed to clarify the clinical characteristics of this pain and perinatal outcomes associated with this phenomenon. METHODS: This was a single-center retrospective analysis of pregnant women with adenomyosis. The incidence of pain onset at adenomyosis lesions, defined as persistent pain at the adenomyosis site with administration of analgesics for pain relief, and its association with perinatal outcomes were analyzed. RESULTS: Among 91 singleton pregnancies with adenomyosis, 12 pregnancies (13.2 %) presented with pain. One pregnancy resulted in second-trimester miscarriage, and 5 of the 11 pregnancies (45 %) developed preeclampsia, which resulted in preterm delivery, and 3 of the 12 pregnancies (25 %) achieved term delivery. The incidence of preeclampsia and preterm delivery was higher in those who experienced pain than in those without (45 % [5/11] vs. 15 % [11/74]; p<0.05, and 73 % [8/11] vs. 34 % [25/74]; p<0.05, respectively). Among women with pain, the maximum C-reactive protein level was significantly higher in women who developed preeclampsia than in those who did not (5.45 vs. 0.12 mg/dL, p<0.05). CONCLUSIONS: Our study revealed that adenomyosis can cause pain in over one of eight pregnancies with adenomyosis, which may be associated with the increased incidence of preeclampsia resulting in preterm delivery. Women with pain, especially those with high C-reactive protein levels, may be at high risk for future development of preeclampsia and consequent preterm delivery.

Increased risk of placenta previa and preterm birth in pregnant women with endometriosis/adenomyosis: A propensity-score matching analysis of a nationwide perinatal database in Japan.

AIM: We aimed to investigate the associations of endometriosis and adenomyosis with pregnancy complications by using a large-scale Japanese database. METHODS: We retrospectively analyzed 145 590 singleton pregnancies from the Japan Perinatal Registry Network Database. Pregnant women registered as having endometriosis or adenomyosis were designated as the case group (EA), whereas the control group (non-EA) was selected using propensity-score matching adjusted for variables such as age, parity, BMI, smoking history, and the use of assisted reproductive technology. The main outcomes included placental malposition, preterm birth, and hypertensive disorders of pregnancy (HDP). RESULTS: In total, 1203 patients from both the EA and non-EA groups were matched and evaluated. The EA group showed significantly higher rates of placenta previa (odds ratio [OR], 3.01; 95% confidence interval [CI], 1.84-4.92), low-lying placenta (OR, 2.02; 95% CI, 1.06-3.86), and preterm birth (OR, 1.44; 95% CI, 1.13-1.84) than the non-EA group. However, no significant difference was observed in the incidence of HDP (OR, 1.22; 95% CI, 0.90-1.66). CONCLUSION: The use of propensity-score matching to analyze a nationwide perinatal database in Japan clarified that EA was associated with increased pregnancy complications, specifically placental malposition, including placenta previa and low-lying placenta, and preterm birth, but not with HDP.

Surgical resection of retinoblastoma-associated bladder leiomyosarcoma during pregnancy: a case report.

BACKGROUND: Management of a bladder tumor during pregnancy is an uncommon clinical situation. Leiomyosarcoma of the urinary bladder is a rare histological type of bladder tumor and a rare secondary cancer in survivors of retinoblastoma (RB). However, there has been no report of RB-associated bladder leiomyosarcoma during pregnancy. CASE PRESENTATION: A 37-year-old pregnant woman with a medical history of RB in infancy presented with gross hematuria at the 17th week of gestation. Cystoscopy revealed a 40-mm papillary tumor on the left lateral wall of the urinary bladder. At the 25th week of gestation, she underwent transurethral resection of the bladder tumor, and the pathological diagnosis was bladder leiomyosarcoma with loss of RB1 expression. At the 31st week of gestation, she gave birth by caesarean section. One month after the delivery (to allow for involution of the uterus), she underwent partial cystectomy, and the specimen contained no residual leiomyosarcoma tissue. CONCLUSIONS: We have reported a case of RB-associated bladder leiomyosarcoma that was successfully treated during and after pregnancy.

Efficacy of prompt administration of cryoprecipitate in severe postpartum hemorrhage of preeclampsia patients.

AIM: Cryoprecipitate (CRYO) is a concentrated preparation of coagulation factors formulated from fresh frozen plasma (FFP), which can replenish coagulation factors rapidly. Preeclampsia (PE) is frequently associated with postpartum hemorrhage (PPH), and the rapid replenishment of coagulation factors is vital in the management. We conducted a retrospective cohort study to determine the efficacy of administering CRYO irrespective of fibrinogen levels in patients with PE who experienced severe PPH. METHODS: Patients with PPH accompanied by PE and those who required red blood cell (RBC) transfusion were included. Cases were divided into two groups: those treated with CRYO (N = 16) and those not treated with CRYO (N = 10). The total transfusion volume, blood loss before and after transfusion initiation, duration of hospitalization, presence of pulmonary edema, and performance of either interventional radiology or hysterectomy were compared. RESULTS: The median fibrinogen levels before transfusion were 2.24 and 2.34 g/L in the CRYO group and the not using group, respectively. Although blood loss before transfusion was comparable between the two groups, blood loss after transfusion was significantly less in the CRYO group (median: 520 vs. 2352 mL, p = 0.015), as well as the total blood loss (median: 2285 vs. 3825 mL, p = 0.005) and total transfusion volume (median: RBC 6 vs. 16 U, p = 0.01, FFP 10 vs. 20 U, p = 0.017). CONCLUSION: Prompt replenishment of coagulation factors using CRYO to patients with PE who experience severe PPH could decrease further bleeding.

Hypertensive disorders of pregnancy in moyamoya disease: A single institution experience.

OBJECTIVE: The characteristics of pregnancy and delivery in patients with moyamoya disease (MMD) remain unclear. We retrospectively investigated perinatal outcomes in patients with MMD to evaluate the risks associated to this condition. MATERIALS AND METHODS: Clinical data of women with MMD who delivered at the University of Tokyo Hospital between 2000 and 2021 were collected. Maternal characteristics including genetic data, obstetric complications, method of delivery and anesthesia, neonatal outcomes, neurological events during pregnancy, delivery, and postpartum course, were reviewed. RESULTS: Thirteen pregnancies with MMD were identified. The median maternal age was 30 years. The initial clinical symptoms were identified as transient ischemic attack, infarction, and headache. Eight patients had a history of bypass surgery. The median gestational age at delivery was 37 weeks. DNA samples were collected from five patients, responsible for six pregnancies. Of these six cases, five had the RNF213 c.14429G > A (p.Arg4810Lys) heterozygous variant. Of the 13 pregnancies, seven had hypertensive disorder of pregnancy (HDP). Additionally, three of five pregnancy cases with RNF213 p.Arg4810Lys heterozygous variant presented with HDP. Nine patients underwent cesarean section, and four delivered vaginally with epidural anesthesia. One case of ischemic stroke was confirmed during the postpartum period. Regarding newborns, neither Apgar scores lower than 7 nor neonatal intensive care unit admissions were reported. CONCLUSIONS: This study suggests that the frequency of HDP is higher in patients with MMD compared to those with normal pregnancies. Strict blood pressure control should be performed in patients with MMD during pregnancy and postpartum period.

Pregnancy-induced hemorrhagic degeneration of adenomyosis.

Uterine fibroids are known to degenerate during pregnancy, but it is unknown if similar pathologic condition occurs in adenomyosis. A 38-year-old para 1 woman exhibited uterine tenderness and a markedly elevated inflammatory response at 22 weeks of gestation. Based on magnetic resonance imaging (MRI) findings indicative of hemorrhagic components in an adenomyosis lesion, we judged these features resulted from degeneration of adenomyosis after excluding the possibility of underlying infection by amniocentesis. Although these symptoms improved with conservative management, nonreassuring fetal status prompted an emergency cesarean section at 27 weeks of gestation. MRI performed 4 months postpartum revealed the degeneration had completely disappeared. The present case confirms the presence of a pathologic condition-transient degeneration in adenomyosis-which is triggered by pregnancy.

Postpartum degeneration of adenomyosis with diffuse cyst-like changes and localized hemorrhage detected by sequential magnetic resonance imaging.

Imaging and histological changes occurring in adenomyosis due to pregnancy are unclear. A 38-year-old nulliparous woman presented with dysmenorrhea and infertility. Pelvic magnetic resonance imaging (MRI) showed diffuse-type adenomyosis. Following pregnancy by in vitro fertilization, she was hospitalized at 23 weeks of gestation due to fetal growth restriction and subsequently diagnosed with preeclampsia. A second MRI performed due to an elevated inflammatory response at 31 weeks of gestation detected no obvious degenerative findings. An emergency cesarean section was performed at 33 weeks of gestation because of nonreassuring fetal status. On postpartum day 2, she showed uterine tenderness with a dramatically elevated inflammatory response. A third MRI showed cyst-like degenerations with hemorrhagic changes without abscess. By postpartum day 7, she was quickly relieved and discharged from the hospital. A fourth MRI at postpartum month 4 confirmed the disappearance of degenerations. This is the first report of imaging findings of early postpartum degeneration of adenomyosis.

The impact of fetal growth restriction in diagnosing preeclampsia on the severity of maternal features.

AIM: We aimed to assess the impact of fetal growth restriction (FGR) as a diagnostic criterion for preeclampsia (PE) on the severity of maternal preeclamptic features by comparing it with other diagnostic criteria for PE, maternal organ dysfunction. METHODS: We performed a retrospective cohort study of singleton pregnancies. Based on the status at diagnosis, PE cases preceded by FGR without maternal organ dysfunction (Group F; n = 28) and those preceded by maternal organ dysfunction without FGR (Group M; n = 87) were analyzed. RESULTS: Group F had an earlier PE diagnosis (32.5 ± 4.9 vs. 36.7 ± 3.5 weeks, p < 0.01) and delivery (33.7 ± 4.5 vs. 37.5 ± 3.1 weeks, p < 0.01) than Group M. No significant differences in maternal morbidities were observed between the groups, including severe hypertension (75.0 vs. 60.0%), need for intravenous antihypertensives (42.9 vs. 48.3%) or magnesium sulfate (60.7 vs. 54.5%), or a composite of major maternal complications (17.9 vs. 21.8%). When limited to early-onset PE diagnosed before 34 weeks of gestation (17 and 17 cases in Group F and M, respectively), the frequencies of maternal morbidities (severe hypertension: 70.6 vs. 52.9%, intravenous antihypertensives: 35.3 vs. 35.3%, magnesium sulfate: 58.8 vs. 47.1%, major complications: 29.4 vs. 23.5%) and the duration from diagnosis until delivery (11.2 ± 14.7 vs. 16.5 ± 21.7 days) were comparable between two groups. CONCLUSIONS: Our results suggest that the presence of FGR on PE diagnosis is associated with the development of severe maternal symptoms as much as that of maternal organ dysfunction at diagnosis, and it may be reasonable to include FGR in PE diagnostic criteria.

Proposed Management Policy for Pregnant Women with Loeys-Dietz Syndrome Following Prophylactic Aortic Root Replacement Based on Experience from a Tertiary Care Center.

Loeys-Dietz syndrome (LDS) is a connective tissue disorder with a high incidence of aortic dissection (AD). After treating two previously reported cases of postpartum AD in women with LDS following prophylactic aortic root replacement (ARR), we succeeded in managing a 30-year-old primigravida with no AD during her peripartum period. On the basis of the patient's stated desire to conceive during preconception counseling, a multidisciplinary team was assembled. She conceived naturally after receiving prophylactic ARR and beta-blocker treatment. Multidisciplinary patient care included precise blood pressure management, continuation of beta-blocker treatment, cardiovascular assessment with echocardiogram, regional anesthesia during labor, prevention of lactation, and resumption of angiotensin II receptor blocker therapy immediately after delivery. On the basis of our assessment of three cases, including this case, and a literature review, we propose a peripartum management strategy for patients with LDS following prophylactic ARR.

Reciprocal upregulation of hypoxia-inducible factor-1α and persistently enhanced placental adenosine signaling contribute to the pathogenesis of preeclampsia.

Recent evidence indicates that elevated placental adenosine signaling contributes to preeclampsia (PE). However, the molecular basis for the chronically enhanced placental adenosine signaling in PE remains unclear. Here, we report that hypoxia-inducible factor-1α (HIF-1α) is crucial for the enhancement of placental adenosine signaling. Utilizing a pharmacologic approach to reduce placental adenosine levels, we found that enhanced adenosine underlies increased placental HIF-1α in an angiotensin receptor type 1 receptor agonistic autoantibody (AT1 -AA)-induced mouse model of PE. Knockdown of placental HIF-1α in vivo suppressed the accumulation of adenosine and increased ecto-5'-nucleotidase (CD73) and adenosine A2B receptor (ADORA2B) in the placentas of PE mouse models induced by AT1 -AA or LIGHT, a TNF superfamily cytokine (TNFSF14). Human in vitro studies using placental villous explants demonstrated that increased HIF-1α resulting from ADORA2B activation facilitates the induction of CD73, ADORA2B, and FLT-1 expression. Overall, we demonstrated that (a) elevated placental HIF-1α by AT1 -AA or LIGHT upregulates CD73 and ADORA2B expression and (b) enhanced adenosine signaling through upregulated ADORA2B induces placental HIF-1α expression, which creates a positive feedback loop that promotes FLT-1 expression leading to disease development. Our results suggest that adenosine-based therapy targeting the malicious cycle of placental adenosine signaling may elicit therapeutic effects on PE.

Pravastatin for preeclampsia: From animal to human.

Preeclampsia is characterized by the emergence of hypertension and proteinuria after 20 weeks of pregnancy, and it threatens both maternal and fetal lives if it proceeds unabated. Despite numerous studies, thus far the only fundamental therapy for preeclampsia is termination of pregnancy, leading to preterm birth. Furthermore, preeclamptic women are reported to be at risk for cardiovascular diseases for 10 years after delivery. Therefore, preventative and therapeutic strategies for preeclampsia are required. Recently, statins have been reported to improve the regeneration of vascular endothelium, and pravastatin has attracted attention as a potential preventative or therapeutic candidate for preeclampsia. Pravastatin has been demonstrated to have preventative effects in preeclampsia model mice, and a large volume of human data from pregnant women taking statins supports the safety of these drugs. Moreover, small clinical trials have reported that pravastatin has strong preventative or therapeutic effects on preeclampsia and it has the potential to improve the prognosis of pregnant women, fetuses and neonates affected by this condition.

Therapeutic potential of combination therapy of soluble VEGF receptor 1 and conventional chemotherapy for ovarian cancer growth.

AIM: This study aimed at evaluating the additional anti-tumor effects of exogenous rVEGFR1 (sFlt1) on conventional chemotherapy in ovarian cancer cell lines. METHODS: We utilized cells from two ovarian cancer cell lines, SKOV3 and HeyA8, and treated them with a combination of rVEGFR1 (sFlt1) and carboplatin as well as rVEGFR1 (sFlt1) alone. First, we evaluated cell survival after treatment by using cell counting and MTS assays. Next, we performed Ki67 staining for evaluating the inhibitory effects of the treatment on cell proliferation, and a lactate dehydrogenase (LDH) assay for evaluating cytotoxicity. Finally, to determine whether MAP kinase signaling is involved in this process, we performed western blot analysis of extracellular signal-regulated kinase (ERK), phospho-ERK, c-jun n-terminal kinase (JNK) and phospho-JNK. RESULTS: The cytotoxic and growth-restriction effects were more pronounced in the group co-administered with rVEGFR1 (sFlt1) and carboplatin than in cells treated with either rVEGFR1 (sFlt1) or carboplatin alone. Quantitative analysis of Ki67-positive cells also showed a decreased proportion of Ki67-positive cells in SKOV3 cells treated with a combination of exogeneous rVEGFR1 (sFlt1) and carboplatin compared to that in cells treated with either rVEGFR1 (sFlt1) or carboplatin alone. In the LDH assay, we also found significantly enhanced cell toxicity from the combination therapy. Finally, western blotting analysis showed that the MAPK signaling pathway was not affected by sFlt1 treatment. CONCLUSION: This study confirmed the additive effects of rVEGFR1 (sFlt1) combined with conventional chemotherapy for ovarian cancer growth in in vitro assays, thus suggesting the combination of rVEGFR1 (sFlt1) and carboplatin as a potential novel therapeutic option for ovarian cancer.

In vivo uterine local gene delivery system using TAT-displaying bionanocapsules.

BACKGROUND: The uterus is an organ that is directly accessible via the transvaginal route, whereas the drug delivery system and the gene delivery system (GDS) for the uterus are very limited, even in animal models. In the present study, we optimized a bionanocapsule (BNC) comprising a hepatitis B virus envelope L-protein particle, for which a structurally similar particle has been used as an immunogen of a conventional HB vaccine worldwide for more than 30 years, as a local uterine GDS using a mouse model. METHODS: To display various antibodies for re-targeting to different cells other than hepatic cells, the pre-S1 region of BNC was replaced with a tandem form of the protein A-derived immunoglobulin G Fc-interacting region (Z domain, ZZ-BNC). To induce strong cell adhesion after local administration into the uterine cavity, ZZ-BNC was modified with a transactivator of transcription (TAT) peptide. RESULTS: Gene transfer using TAT-modified ZZ-BNC is approximately 5000- or 18-fold more efficient than the introduction of the same dose of naked DNAs or the use of the cationic liposomes, respectively. TAT-modified ZZ-BNC was rapidly eliminated from the uterus and had no effect on the pregnancy rate, litter size or fetal growth. CONCLUSIONS: TAT-modified ZZ-BNC could be a useful GDS for uterine endometrial therapy via local uterine injection.

Endothelin-1 profiles in advanced maternal age complicated with hypertensive disorders of pregnancy.

Recently, advanced maternal age (AMA) has been increasing due to late marriage and assisted reproductive technology. AMA is high-risk pregnancy associated with the life-threatening diseases such as hypertensive disorders of pregnancy (HDP). Recently we have reported novel AMA model mice using aged spontaneous pregnant mice, and found that the phenotypes of AMA model mice reflect the same characteristics as human AMA. We have also demonstrated that atypical angiogenic factors profiles including soluble VEGF-R1 (sFlt-1) and placental growth factor in both AMA pregnant women and AMA model mice. VEGF-endothelin-1 system have been also known as one of HDP-associated factors, however, there has been few reports on the relation between VEGF-endothelin-1 system and AMA. In this study, we investigated the profiles of VEGF-endothelin-1 system using our model mice's samples. As a result, VEGF and endothelin-1 levels were not significantly different between AMA and young individuals. Our results indicated that the mechanisms of hypertension in AMA may differ from those in young individuals from the point of VEGF-endothelin-1 system.

Trophoblast-Specific Conditional Atg7 Knockout Mice Develop Gestational Hypertension.

Hypertensive disorder of pregnancy (HDP) is a serious pregnancy complication that is life threatening to both the mother and fetus. Understanding HDP pathophysiology is important for developing medical treatments. This study demonstrates the involvement of autophagy deficiency in adverse maternal and fetal outcomes using trophoblast-specific autophagy related (Atg)7, an autophagy-related protein, knockout mice. Atg7 conditional knockout (cKO) placentas were significantly smaller than controls in the spongiotrophoblast layer but not the labyrinth layer, which significantly elevated blood pressure in dams. A marker of autophagy deficiency, sequestosome 1/p62, was accumulated in giant trophoblast cells and in the spongiotrophoblast layer, accompanying increased apoptosis. However, neither proteinuria in dams nor fetal growth restriction was observed. Regarding trophoblast function, the number of trophoblasts migrating into the maternal decidua was significantly reduced, and the wall/lumen ratio of the spiral arteries was significantly increased in cKO placentas, suggesting shallow trophoblast invasion and inadequate vascular remodeling. The relative expression of placental growth factor mRNA was significantly decreased in cKO placentas compared with the control, likely causing poor placentation; however, other factors were unchanged in cKO placentas. This is the first report of autophagy deficiency leading to impaired placentation complicated by maternal HDP attributable to trophoblast dysfunction, and it suggests that placental autophagy is required for normal placentation.

Preeclampsia: Maternal Systemic Vascular Disorder Caused by Generalized Endothelial Dysfunction Due to Placental Antiangiogenic Factors.

Preeclampsia, a systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, is the leading cause of maternal and perinatal morbidity and mortality. Maternal endothelial dysfunction caused by placental factors has long been accepted with respect to the pathophysiology of preeclampsia. Over the past decade, increased production of placental antiangiogenic factors has been identified as a placental factor leading to maternal endothelial dysfunction and systemic vascular dysfunction. This review summarizes the recent advances in understanding the molecular mechanisms of endothelial dysfunction caused by placental antiangiogenic factors, and the novel clinical strategies based on these discoveries.

Soluble FLT-1 rules placental destiny.

INTRODUCTION: Placenta previa is an abnormality in which the placenta covers the internal uterine os, and it can cause serious morbidity and mortality in both mother and fetus due to catastrophic hemorrhage. Some pregnant women recover from placenta previa due to a phenomenon called "migration." However, the mechanism of "migration" of the placenta has not been elucidated. METHODS: Human placentas were collected from patients with placenta previa and those with no abnormal placentation (control). A microarray analysis was performed to detect the genes up- or down-regulated only in the caudal part in the previa group. Specific mRNA expression was evaluated using real-time quantitative reverse transcription PCR (qRT-PCR). Unilateral uterine artery ablation of 8.5 dpc mice was performed to reproduce the reduction of placental blood supply, and weights of the placentas and fetuses were evaluated in 18.5 dpc. Specific mRNA expression was also evaluated in mice placentas. RESULTS: According to the result of the microarray analysis, we focused on soluble fms-like tyrosine kinase-1 (sFLT-1) and hypoxia-inducible factor-1 (HIF-1) alpha. The sFLT-1 expression level is locally high in the caudal part of the human placenta in patients with placenta previa. In mice experiments, the weights of the placentas and fetuses were significantly smaller in the ablation side than those in the control side, and the sFlt-1 expression level was significantly higher in the ablation side than in the control side. DISCUSSION: Our study suggests that "migration" of the placenta is derived from placental degeneration at the caudal part of the placenta, and sFlt-1 plays a role in this placental degeneration.

Arginase controls soluble vascular endothelial growth factor receptor 1 (sFlt1) to maintain pregnancy homeostasis.

Excessive soluble fms-like tyrosine kinase-1 (sFlt-1) has been strongly implicated in preeclampsia. An increase in the serum sFlt-1 level occurs before the onset of preeclampsia, and the sFlt-1 level is already higher in women who are predisposed to preeclampsia than in normotensive pregnant women. This study aimed to investigate the relation between arginase and sFlt-1 in the plasma of preeclamptic women and normotensive pregnant women. We suggested that a regulatory mechanism exists that suppresses the level of sFlt-1. The relationship between arginase, one of the nitric oxide (NO) modulators, and sFlt-1 was examined. First, the pregnant women were divided into 4 groups: group 1, sFlt-1 <6000 pg/ml and arginase activity <110 U/L; group 2, sFlt-1 ≥6000 pg/ml and arginase activity <110 U/L; group 3, sFlt-1 ≥6000 pg/ml and arginase activity ≥110 U/L; and group 4, sFlt-1 <6000 pg/ml and arginase activity ≥110 U/L. Groups 2 and 3 comprised preeclamptic women. The preeclampsia/normotensive ratio increased from groups 1 to 3. Under the higher sFlt-1 condition, lower arginase activity was associated with lower occurrence of preeclampsia. Next, in human umbilical endothelial vein cells (HUVECs), a slightly higher concentration of sFlt-1, as in group 2, reduced arginase expression and arginase activity, and S-(2-boronoethyl)-l-cysteine (BEC; arginase inhibitor) impaired sFlt-1 secretion. In contrast, a higher level of sFlt-1 increased arginase expression and activity in HUVECs, as in group 3. These results showed that arginase controlled sFlt-1 elevation to some extent. In conclusion, our results suggest the existence of a mechanism to maintain the level of sFlt-1. Soluble Flt-1 negatively regulated itself against increasing serum sFlt-1 in preeclampsia. Moreover, this study revealed that arginase inhibitors are a potential treatment option for preeclampsia.

Vaginal bioelectrical impedance determines uterine receptivity in mice.

STUDY QUESTION: Can vaginal bioelectrical impedance (VZ) electrophysiologically determine alterations of the endometrium in preparation for implantation? SUMMARY ANSWER: VZ can electrophysiologically detect the sulfation and sialylation changes in the uterine glycocalyx in preparation for implantation. WHAT IS KNOWN ALREADY: Uterine receptivity is associated with various glycosylation changes that affect negative charge density at the luminal epithelial cell surface. VZ has been used to monitor the oestrous cycle. STUDY DESIGN, SIZE, DURATION: Pathogen-free Jcl:ICR mice, aged 8-10 weeks, were used in this study. We conducted the following three steps to test our hypothesis that VZ may be used to determine uterine receptivity. First, to investigate whether VZ could determine alteration of sulfation and sialylation in the uterine glycocalyx, VZ was measured in mice with induced artificial sulfation and sialylation changes in the uterine glycocalyx (galactose-3-O-sulfotransferase 2 (GP3ST) + α(1,3/1,4) fucosyltransferase gene (FucT-III)-transferred group (n = 15) and in LacZ (encoding for ß-galactosidase)-transferred mice as a control group (n = 12)). Second, to investigate whether VZ could determine alterations of the endometrium in preparation for implantation, we measured VZ during the early stage of pregnancy (n = 12 each). Third, to investigate whether VZ could be used to evaluate uterine receptivity prospectively, VZ was measured in an implantation failure model mice. In 21 mice, local and transient suppression of signal transducer and activator of transcription-3 (Stat3) in the uterus were evaluated 1 day before implantation began, and 23 scramble decoy-transferred mice were used as a control group. PARTICIPANTS/MATERIALS, SETTING, METHODS: The VZ was measured at a frequency of 1 kHz in Jcl:ICR mice. Data were analysed using the Kruskal-Wallis test with Dunn's multiple comparisons, or the Student's t-test or Wilcoxon's rank-sum test with the Shapiro-Wilk normality test. The values of VZ were analysed using receiver operating characteristic (ROC) curve analysis to identify the optimal cut-off point to determine if this parameter predicted non-pregnancy. MAIN RESULTS AND THE ROLE OF CHANCE: Sulfation and sialylation changes induced in the luminal epithelial glycocalyx decreased the value of VZ. VZ showed a significant daily decrease during the early stage of pregnancy (Day 1.5 versus 2.5 p.c.: P < 0.005; Student's t-test, Day 2.5 versus 3.5 p.c.: P < 0.001; Wilcoxon's rank-sum test, Day 3.5 versus 4.5 p.c.: P < 0.005; Student's t-test, Day 4.5 versus 5.5 p.c.: P < 0.05; Student's t-test). One day before implantation began, VZ in the implantation failure model mice was significantly higher than in the control mice (P < 0.001, Wilcoxon's rank-sum test). The ROC curve analysis of VZ as a predictor of non-conception showed areas under the ROC curve of 0.91 (95% CI: 0.83-0.99). LIMITATIONS, REASONS FOR CAUTION: Although it is influenced by surface charge in the uterine epithelium, the mechanism whereby VZ changes during early pregnancy is still unexplained. WIDER IMPLICATIONS OF THE FINDINGS: Local bioelectrical impedance may help to prospectively evaluate uterine receptivity in women. Including the measurement of local bioelectrical impedance as part of a frozen-thawed embryo transfer strategy may improve the efficiency of ART. STUDY FUNDING/COMPETING INTEREST(S): This work was supported in part by the Japan Society for the Promotion of Science JSPS KAKENHI Grant (Nos. 19390429, 21390453, 16K11086 and 16K11087) from the Ministry of Education, Science and Culture of Japan (Tokyo, Japan) and Suzuken Memorial Foundation (Nagoya, Japan). The authors declare that they have no conflict of interest.

Prospective evaluation of uterine receptivity in mice.

In current infertility treatments it is necessary to evaluate uterine receptivity in each menstrual cycle. During the implantation period, the uterus goes through many complex orchestrated changes, including changes to the glycocalyx. The changes to the glycocalyx are due to sialylation, sulfation and fucosylation. Can the measurement of in-vivo uterine pH and/or oxidation-reduction potential (ORP) determine the alterations of uterine endometrium for implantation and evaluate prospective uterine receptivity? In the present study we assessed in vivo uterine pH and ORP during the early stages of pregnancy in naïve mice, as well as in a murine model of implantation failure created by local and transient suppression of signal transducer and activator of transcription 3. There was no change in the in vivo uterine pH between post-coitus Days 2 and 6. In vivo uterine ORP was significantly higher compared to the day before. One day before implantation began, uterine ORP was significantly decreased in the implantation failure group compared with the naïve and control groups. Receiver operator characteristic (ROC) curve analysis of uterine ORP as a predictor of non-conception showed an area under the ROC curve of 0.96 (95% confidence interval 0.92-1.00). Thus, in vivo uterine ORP could be a parameter to prospectively evaluate uterine receptivity.